How long it takes to break in Cary 303/200

I recently bought a Cary 303/200 (which I posted a few days ago). I notice the high's are a bit bright. I figure it takes sometimes the sound to settle down but how long in your opinion? The sound still has a outer edge, a slight tizzy outline especially on female vocals.
Probably 50-100 hours will do it. matching with other components of your system, such as speakers and cables are also crucial, besides breaking in of Cary.